If you thought brafree exercising was extreme, take a look at this website:
which advocates bra-free exercise on a mini-trampoline. Make sure to scroll down all the way to the bottom of the page (past a big gap), where they discuss why brafree is so healthy.
Although I have two friends who do aerobics at size DD, brafree exercise doesn't have to be all-or-nothing. Even brafree walking will get your circulation moving. After a few weeks of brafreedom, you might be surprised at what you can do brafree, even if it doesn't involve a trampoline or running marathons. Best wishes!